Wilfred dawson



May 26, 1931.

W. DAWSON ELECTRIC LAMP Filed May 23, 1927 Patented May 26, 1931 UNITED STATES PATENT OFFICE WILFRED DAWSON, or noNnoN, ENGLAND ELECTRIC LAMP Application filed May 23, 1927, Serial No. 193,586, and in Great Britain ma 31, 71926.

This invention relates to electric lamps of a the multiple filament type and has for its' main object to provide caps provided with improved means whereby the different filaa) ments may be selectively brought into cir cuit while retaining the standard forms of lamp holder.

A further object is to provide relatively In the accompanying drawings which illustrate the invention,

Fig. 1 represents in elevation the upper or cap portion of a three-filament lamp constructed in accordance with the invention.

Fig. 2 is a sectional plan corresponding to Fig. 1.

In the lamp illustrated inFigs. 1 and 2 the cap comprises an upper metal sleeve A and a lower metal sleeve B the joint (1 between the two sleeves being such as to allow rotary but not longitudinal movement.

The sleeve A is provided with the usual contacts 6, c for a bayonet fitting and one of these a is connected direct to the leadingin wire (2 which is common to the three filaments.

The other contact I; is connected to a con tact arm h of springy metal the lower por- 40 tion of which extends radially in relation to the cap and is provided with a contact 2', preferably of V form on the underside.

The lower sleeve B hassecured to it an arcuate block is of porcelain, fibre or other suitable insulating material and this block carries three contact studs Z, m, n to which the leading-in wires 6, f, g of the separate filaments are connected. These studs are equally spaced and are adapted successively to engage the contact 2' on the arm h as the sleeve B is turned relatively to the sleeve A. Radial grooves 0 are preferably provided on the top surface of the block is to enable the contact i to click into the various on and off positions and end stops 1) are also provided on the block.

In order to'bring different filaments or portions of a filament into circuit, the sleeve B is turned relatively to the sleeve A until the contact 2' engages the stud corresponding to the filament which is required to be brought into circuit. In this slight movement the wire d will bend sufficiently without overstraining it, but if desired this wiremay bebrought up to an arcuate contact plate with which a contact arm carried by the contact 0' will maintain engagement. 7 i

' It is to be understood that the invention is not restricted to the exact details shown and described but embraces such modifications as come within the ambit of the accompanying claims.

I claim 1. An electric lamp of the multiple filament type having a common leading-in wire and other leading-in wires comprising an upper sleeve shaped at its upper end for engagement with a standard socket and formed at its lower end of larger diameter than said standard lamp socket, a lower sleeve of larger diameter than the standard socket rotatably connected to said lower larger diameter end of said upper socket and con tact means carried by said lower sleeve for selectively bringing into contact one of said other return wires.

2. An electric lamp of the multiple filament type having a common leading-in wire and other leading-in wires comprising an upper sleeve shaped at its upper end for engagement with a standard lamp socket, and formed at its lower end of larger diameter than said standard lamp socket, a lower sleeve of larger diameter than the standard socket rotatably connected to said lower larger diameter end of said upper socket, an arcuate insulated block carried by the lower sleeve and carrying a series of contacts each connected to said other leading-in wires, and

a radial contact arm carried by said upper sleeve and connected to one of the lampholder sockets and capable of selective engagement with the contacts carried by the arcuate insulated blocks by rotation of said lower sleeve.

3. An electric lamp of the multiple filament typehaving a common leading-in wire and other leading-in wires, including an upper sleeve shaped at its upper end for engagement with a standard lamp socket and formed in its lower portion of larger diameter than that of the standard lamp socket, a lower sleeve of larger diameter than the standard lamp socket and connected to and mounted for independent rotation with respect to the upper sleeve, an arcuate insulated. block secured to the interior of the wall of the lower sleeve, a series of contacts carried by said block and corresponding in number to the number of other leading-in wires referred to, and a screw threaded through the block and electrically engaging each contact, each of said screws forming a terminal for each of said other leading-in wires, and a yieldingly mounted contact arm secured at one end to the upper sleeve for circuiting connections and cooperating at its opposite end with said contacts as selectively positioned by the relative rotation of said lower sleeve.

In testimony whereof I atfix my signature.

VVILFRED DAWSON. 

